// SPDX-License-Identifier: GPL-2.0+ /* * Multifunction core driver for Zodiac Inflight Innovations RAVE * Supervisory Processor(SP) MCU that is connected via dedicated UART * port * * Copyright (C) 2017 Zodiac Inflight Innovations */ #include <linux/atomic.h> #include <linux/crc-ccitt.h> #include <linux/delay.h> #include <linux/export.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/kernel.h> #include <linux/mfd/rave-sp.h> #include <linux/module.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/sched.h> #include <linux/serdev.h> #include <asm/unaligned.h> /* * UART protocol using following entities: * - message to MCU => ACK response * - event from MCU => event ACK * * Frame structure: * <STX> <DATA> <CHECKSUM> <ETX> * Where: * - STX - is start of transmission character * - ETX - end of transmission * - DATA - payload * - CHECKSUM - checksum calculated on <DATA> * * If <DATA> or <CHECKSUM> contain one of control characters, then it is * escaped using <DLE> control code. Added <DLE> does not participate in * checksum calculation. */ #define RAVE_SP_STX 0x02 #define RAVE_SP_ETX 0x03 #define RAVE_SP_DLE 0x10 #define RAVE_SP_MAX_DATA_SIZE 64 #define RAVE_SP_CHECKSUM_8B2C 1 #define RAVE_SP_CHECKSUM_CCITT 2 #define RAVE_SP_CHECKSUM_SIZE RAVE_SP_CHECKSUM_CCITT /* * We don't store STX, ETX and unescaped bytes, so Rx is only * DATA + CSUM */ #define RAVE_SP_RX_BUFFER_SIZE \ (RAVE_SP_MAX_DATA_SIZE + RAVE_SP_CHECKSUM_SIZE) #define RAVE_SP_STX_ETX_SIZE 2 /* * For Tx we have to have space for everything, STX, EXT and * potentially stuffed DATA + CSUM data + csum */ #define RAVE_SP_TX_BUFFER_SIZE \ (RAVE_SP_STX_ETX_SIZE + 2 * RAVE_SP_RX_BUFFER_SIZE) /** * enum rave_sp_deframer_state - Possible state for de-framer * * @RAVE_SP_EXPECT_SOF: Scanning input for start-of-frame marker * @RAVE_SP_EXPECT_DATA: Got start of frame marker, collecting frame * @RAVE_SP_EXPECT_ESCAPED_DATA: Got escape character, collecting escaped byte */ enum rave_sp_deframer_state { RAVE_SP_EXPECT_SOF, RAVE_SP_EXPECT_DATA, RAVE_SP_EXPECT_ESCAPED_DATA, }; /** * struct rave_sp_deframer - Device protocol deframer * * @state: Current state of the deframer * @data: Buffer used to collect deframed data * @length: Number of bytes de-framed so far */ struct rave_sp_deframer { enum rave_sp_deframer_state state; unsigned char data[RAVE_SP_RX_BUFFER_SIZE]; size_t length; }; /** * struct rave_sp_reply - Reply as per RAVE device protocol * * @length: Expected reply length * @data: Buffer to store reply payload in * @code: Expected reply code * @ackid: Expected reply ACK ID * @completion: Successful reply reception completion */ struct rave_sp_reply { size_t length; void *data; u8 code; u8 ackid; struct completion received; }; /** * struct rave_sp_checksum - Variant specific checksum implementation details * * @length: Calculated checksum length * @subroutine: Utilized checksum algorithm implementation */ struct rave_sp_checksum { size_t length; void (*subroutine)(const u8 *, size_t, u8 *); }; struct rave_sp_version { u8 hardware; __le16 major; u8 minor; u8 letter[2]; } __packed; struct rave_sp_status { struct rave_sp_version bootloader_version; struct rave_sp_version firmware_version; u16 rdu_eeprom_flag; u16 dds_eeprom_flag; u8 pic_flag; u8 orientation; u32 etc; s16 temp[2]; u8 backlight_current[3]; u8 dip_switch; u8 host_interrupt; u16 voltage_28; u8 i2c_device_status; u8 power_status; u8 general_status; u8 deprecated1; u8 power_led_status; u8 deprecated2; u8 periph_power_shutoff; } __packed; /** * struct rave_sp_variant_cmds - Variant specific command routines * * @translate: Generic to variant specific command mapping routine * @get_status: Variant specific implementation of CMD_GET_STATUS */ struct rave_sp_variant_cmds { int (*translate)(enum rave_sp_command); int (*get_status)(struct rave_sp *sp, struct rave_sp_status *); }; /** * struct rave_sp_variant - RAVE supervisory processor core variant * * @checksum: Variant specific checksum implementation * @cmd: Variant specific command pointer table * */ struct rave_sp_variant { const struct rave_sp_checksum *checksum; struct rave_sp_variant_cmds cmd; }; /** * struct rave_sp - RAVE supervisory processor core * * @serdev: Pointer to underlying serdev * @deframer: Stored state of the protocol deframer * @ackid: ACK ID used in last reply sent to the device * @bus_lock: Lock to serialize access to the device * @reply_lock: Lock protecting @reply * @reply: Pointer to memory to store reply payload * * @variant: Device variant specific information * @event_notifier_list: Input event notification chain * * @part_number_firmware: Firmware version * @part_number_bootloader: Bootloader version */ struct rave_sp { struct serdev_device *serdev; struct rave_sp_deframer deframer; atomic_t ackid; struct mutex bus_lock; struct mutex reply_lock; struct rave_sp_reply *reply; const struct rave_sp_variant *variant; struct blocking_notifier_head event_notifier_list; const char *part_number_firmware; const char *part_number_bootloader; }; static bool rave_sp_id_is_event(u8 code) { return (code & 0xF0) == RAVE_SP_EVNT_BASE; } static void rave_sp_unregister_event_notifier(struct device *dev, void *res) { struct rave_sp *sp = dev_get_drvdata(dev->parent); struct notifier_block *nb = *(struct notifier_block **)res; struct blocking_notifier_head *bnh = &sp->event_notifier_list; WARN_ON(blocking_notifier_chain_unregister(bnh, nb)); } int devm_rave_sp_register_event_notifier(struct device *dev, struct notifier_block *nb) { struct rave_sp *sp = dev_get_drvdata(dev->parent); struct notifier_block **rcnb; int ret; rcnb = devres_alloc(rave_sp_unregister_event_notifier, sizeof(*rcnb), GFP_KERNEL); if (!rcnb) return -ENOMEM; ret = blocking_notifier_chain_register(&sp->event_notifier_list, nb); if (!ret) { *rcnb = nb; devres_add(dev, rcnb); } else { devres_free(rcnb); } return ret; } EXPORT_SYMBOL_GPL(devm_rave_sp_register_event_notifier); static void csum_8b2c(const u8 *buf, size_t size, u8 *crc) { *crc = *buf++; size--; while (size--) *crc += *buf++; *crc = 1 + ~(*crc); } static void csum_ccitt(const u8 *buf, size_t size, u8 *crc) { const u16 calculated = crc_ccitt_false(0xffff, buf, size); /* * While the rest of the wire protocol is little-endian, * CCITT-16 CRC in RDU2 device is sent out in big-endian order. */ put_unaligned_be16(calculated, crc); } static void *stuff(unsigned char *dest, const unsigned char *src, size_t n) { while (n--) { const unsigned char byte = *src++; switch (byte) { case RAVE_SP_STX: case RAVE_SP_ETX: case RAVE_SP_DLE: *dest++ = RAVE_SP_DLE; /* FALLTHROUGH */ default: *dest++ = byte; } } return dest; } static int rave_sp_write(struct rave_sp *sp, const u8 *data, u8 data_size) { const size_t checksum_length = sp->variant->checksum->length; unsigned char frame[RAVE_SP_TX_BUFFER_SIZE]; unsigned char crc[RAVE_SP_CHECKSUM_SIZE]; unsigned char *dest = frame; size_t length; if (WARN_ON(checksum_length > sizeof(crc))) return -ENOMEM; if (WARN_ON(data_size > sizeof(frame))) return -ENOMEM; sp->variant->checksum->subroutine(data, data_size, crc); *dest++ = RAVE_SP_STX; dest = stuff(dest, data, data_size); dest = stuff(dest, crc, checksum_length); *dest++ = RAVE_SP_ETX; length = dest - frame; print_hex_dump_debug("rave-sp tx: ", DUMP_PREFIX_NONE, 16, 1, frame, length, false); return serdev_device_write(sp->serdev, frame, length, HZ); } static u8 rave_sp_reply_code(u8 command) { /* * There isn't a single rule that describes command code -> * ACK code transformation, but, going through various * versions of ICDs, there appear to be three distinct groups * that can be described by simple transformation. */ switch (command) { case 0xA0 ... 0xBE: /* * Commands implemented by firmware found in RDU1 and * older devices all seem to obey the following rule */ return command + 0x20; case 0xE0 ... 0xEF: /* * Events emitted by all versions of the firmare use * least significant bit to get an ACK code */ return command | 0x01; default: /* * Commands implemented by firmware found in RDU2 are * similar to "old" commands, but they use slightly * different offset */ return command + 0x40; } } int rave_sp_exec(struct rave_sp *sp, void *__data, size_t data_size, void *reply_data, size_t reply_data_size) { struct rave_sp_reply reply = { .data = reply_data, .length = reply_data_size, .received = COMPLETION_INITIALIZER_ONSTACK(reply.received), }; unsigned char *data = __data; int command, ret = 0; u8 ackid; command = sp->variant->cmd.translate(data[0]); if (command < 0) return command; ackid = atomic_inc_return(&sp->ackid); reply.ackid = ackid; reply.code = rave_sp_reply_code((u8)command), mutex_lock(&sp->bus_lock); mutex_lock(&sp->reply_lock); sp->reply = &reply; mutex_unlock(&sp->reply_lock); data[0] = command; data[1] = ackid; rave_sp_write(sp, data, data_size); if (!wait_for_completion_timeout(&reply.received, HZ)) { dev_err(&sp->serdev->dev, "Command timeout\n"); ret = -ETIMEDOUT; mutex_lock(&sp->reply_lock); sp->reply = NULL; mutex_unlock(&sp->reply_lock); } mutex_unlock(&sp->bus_lock); return ret; } EXPORT_SYMBOL_GPL(rave_sp_exec); static void rave_sp_receive_event(struct rave_sp *sp, const unsigned char *data, size_t length) { u8 cmd[] = { [0] = rave_sp_reply_code(data[0]), [1] = data[1], }; rave_sp_write(sp, cmd, sizeof(cmd)); blocking_notifier_call_chain(&sp->event_notifier_list, rave_sp_action_pack(data[0], data[2]), NULL); } static void rave_sp_receive_reply(struct rave_sp *sp, const unsigned char *data, size_t length) { struct device *dev = &sp->serdev->dev; struct rave_sp_reply *reply; const size_t payload_length = length - 2; mutex_lock(&sp->reply_lock); reply = sp->reply; if (reply) { if (reply->code == data[0] && reply->ackid == data[1] && payload_length >= reply->length) { /* * We are relying on memcpy(dst, src, 0) to be a no-op * when handling commands that have a no-payload reply */ memcpy(reply->data, &data[2], reply->length); complete(&reply->received); sp->reply = NULL; } else { dev_err(dev, "Ignoring incorrect reply\n"); dev_dbg(dev, "Code: expected = 0x%08x received = 0x%08x\n", reply->code, data[0]); dev_dbg(dev, "ACK ID: expected = 0x%08x received = 0x%08x\n", reply->ackid, data[1]); dev_dbg(dev, "Length: expected = %zu received = %zu\n", reply->length, payload_length); } } mutex_unlock(&sp->reply_lock); } static void rave_sp_receive_frame(struct rave_sp *sp, const unsigned char *data, size_t length) { const size_t checksum_length = sp->variant->checksum->length; const size_t payload_length = length - checksum_length; const u8 *crc_reported = &data[payload_length]; struct device *dev = &sp->serdev->dev; u8 crc_calculated[RAVE_SP_CHECKSUM_SIZE]; if (unlikely(checksum_length > sizeof(crc_calculated))) { dev_warn(dev, "Checksum too long, dropping\n"); return; } print_hex_dump_debug("rave-sp rx: ", DUMP_PREFIX_NONE, 16, 1, data, length, false); if (unlikely(length <= checksum_length)) { dev_warn(dev, "Dropping short frame\n"); return; } sp->variant->checksum->subroutine(data, payload_length, crc_calculated); if (memcmp(crc_calculated, crc_reported, checksum_length)) { dev_warn(dev, "Dropping bad frame\n"); return; } if (rave_sp_id_is_event(data[0])) rave_sp_receive_event(sp, data, length); else rave_sp_receive_reply(sp, data, length); } static int rave_sp_receive_buf(struct serdev_device *serdev, const unsigned char *buf, size_t size) { struct device *dev = &serdev->dev; struct rave_sp *sp = dev_get_drvdata(dev); struct rave_sp_deframer *deframer = &sp->deframer; const unsigned char *src = buf; const unsigned char *end = buf + size; while (src < end) { const unsigned char byte = *src++; switch (deframer->state) { case RAVE_SP_EXPECT_SOF: if (byte == RAVE_SP_STX) deframer->state = RAVE_SP_EXPECT_DATA; break; case RAVE_SP_EXPECT_DATA: /* * Treat special byte values first */ switch (byte) { case RAVE_SP_ETX: rave_sp_receive_frame(sp, deframer->data, deframer->length); /* * Once we extracted a complete frame * out of a stream, we call it done * and proceed to bailing out while * resetting the framer to initial * state, regardless if we've consumed * all of the stream or not. */ goto reset_framer; case RAVE_SP_STX: dev_warn(dev, "Bad frame: STX before ETX\n"); /* * If we encounter second "start of * the frame" marker before seeing * corresponding "end of frame", we * reset the framer and ignore both: * frame started by first SOF and * frame started by current SOF. * * NOTE: The above means that only the * frame started by third SOF, sent * after this one will have a chance * to get throught. */ goto reset_framer; case RAVE_SP_DLE: deframer->state = RAVE_SP_EXPECT_ESCAPED_DATA; /* * If we encounter escape sequence we * need to skip it and collect the * byte that follows. We do it by * forcing the next iteration of the * encompassing while loop. */ continue; } /* * For the rest of the bytes, that are not * speical snoflakes, we do the same thing * that we do to escaped data - collect it in * deframer buffer */ /* FALLTHROUGH */ case RAVE_SP_EXPECT_ESCAPED_DATA: if (deframer->length == sizeof(deframer->data)) { dev_warn(dev, "Bad frame: Too long\n"); /* * If the amount of data we've * accumulated for current frame so * far starts to exceed the capacity * of deframer's buffer, there's * nothing else we can do but to * discard that data and start * assemblying a new frame again */ goto reset_framer; } deframer->data[deframer->length++] = byte; /* * We've extracted out special byte, now we * can go back to regular data collecting */ deframer->state = RAVE_SP_EXPECT_DATA; break; } } /* * The only way to get out of the above loop and end up here * is throught consuming all of the supplied data, so here we * report that we processed it all. */ return size; reset_framer: /* * NOTE: A number of codepaths that will drop us here will do * so before consuming all 'size' bytes of the data passed by * serdev layer. We rely on the fact that serdev layer will * re-execute this handler with the remainder of the Rx bytes * once we report actual number of bytes that we processed. */ deframer->state = RAVE_SP_EXPECT_SOF; deframer->length = 0; return src - buf; } static int rave_sp_rdu1_cmd_translate(enum rave_sp_command command) { if (command >= RAVE_SP_CMD_STATUS && command <= RAVE_SP_CMD_CONTROL_EVENTS) return command; return -EINVAL; } static int rave_sp_rdu2_cmd_translate(enum rave_sp_command command) { if (command >= RAVE_SP_CMD_GET_FIRMWARE_VERSION && command <= RAVE_SP_CMD_GET_GPIO_STATE) return command; if (command == RAVE_SP_CMD_REQ_COPPER_REV) { /* * As per RDU2 ICD 3.4.47 CMD_GET_COPPER_REV code is * different from that for RDU1 and it is set to 0x28. */ return 0x28; } return rave_sp_rdu1_cmd_translate(command); } static int rave_sp_default_cmd_translate(enum rave_sp_command command) { /* * All of the following command codes were taken from "Table : * Communications Protocol Message Types" in section 3.3 * "MESSAGE TYPES" of Rave PIC24 ICD. */ switch (command) { case RAVE_SP_CMD_GET_FIRMWARE_VERSION: return 0x11; case RAVE_SP_CMD_GET_BOOTLOADER_VERSION: return 0x12; case RAVE_SP_CMD_BOOT_SOURCE: return 0x14; case RAVE_SP_CMD_SW_WDT: return 0x1C; case RAVE_SP_CMD_PET_WDT: return 0x1D; case RAVE_SP_CMD_RESET: return 0x1E; case RAVE_SP_CMD_RESET_REASON: return 0x1F; case RAVE_SP_CMD_RMB_EEPROM: return 0x20; default: return -EINVAL; } } static const char *devm_rave_sp_version(struct device *dev, struct rave_sp_version *version) { /* * NOTE: The format string below uses %02d to display u16 * intentionally for the sake of backwards compatibility with * legacy software. */ return devm_kasprintf(dev, GFP_KERNEL, "%02d%02d%02d.%c%c\n", version->hardware, le16_to_cpu(version->major), version->minor, version->letter[0], version->letter[1]); } static int rave_sp_rdu1_get_status(struct rave_sp *sp, struct rave_sp_status *status) { u8 cmd[] = { [0] = RAVE_SP_CMD_STATUS, [1] = 0 }; return rave_sp_exec(sp, cmd, sizeof(cmd), status, sizeof(*status)); } static int rave_sp_emulated_get_status(struct rave_sp *sp, struct rave_sp_status *status) { u8 cmd[] = { [0] = RAVE_SP_CMD_GET_FIRMWARE_VERSION, [1] = 0, }; int ret; ret = rave_sp_exec(sp, cmd, sizeof(cmd), &status->firmware_version, sizeof(status->firmware_version)); if (ret) return ret; cmd[0] = RAVE_SP_CMD_GET_BOOTLOADER_VERSION; return rave_sp_exec(sp, cmd, sizeof(cmd), &status->bootloader_version, sizeof(status->bootloader_version)); } static int rave_sp_get_status(struct rave_sp *sp) { struct device *dev = &sp->serdev->dev; struct rave_sp_status status; const char *version; int ret; ret = sp->variant->cmd.get_status(sp, &status); if (ret) return ret; version = devm_rave_sp_version(dev, &status.firmware_version); if (!version) return -ENOMEM; sp->part_number_firmware = version; version = devm_rave_sp_version(dev, &status.bootloader_version); if (!version) return -ENOMEM; sp->part_number_bootloader = version; return 0; } static const struct rave_sp_checksum rave_sp_checksum_8b2c = { .length = 1, .subroutine = csum_8b2c, }; static const struct rave_sp_checksum rave_sp_checksum_ccitt = { .length = 2, .subroutine = csum_ccitt, }; static const struct rave_sp_variant rave_sp_legacy = { .checksum = &rave_sp_checksum_ccitt, .cmd = { .translate = rave_sp_default_cmd_translate, .get_status = rave_sp_emulated_get_status, }, }; static const struct rave_sp_variant rave_sp_rdu1 = { .checksum = &rave_sp_checksum_8b2c, .cmd = { .translate = rave_sp_rdu1_cmd_translate, .get_status = rave_sp_rdu1_get_status, }, }; static const struct rave_sp_variant rave_sp_rdu2 = { .checksum = &rave_sp_checksum_ccitt, .cmd = { .translate = rave_sp_rdu2_cmd_translate, .get_status = rave_sp_emulated_get_status, }, }; static const struct of_device_id rave_sp_dt_ids[] = { { .compatible = "zii,rave-sp-niu", .data = &rave_sp_legacy }, { .compatible = "zii,rave-sp-mezz", .data = &rave_sp_legacy }, { .compatible = "zii,rave-sp-esb", .data = &rave_sp_legacy }, { .compatible = "zii,rave-sp-rdu1", .data = &rave_sp_rdu1 }, { .compatible = "zii,rave-sp-rdu2", .data = &rave_sp_rdu2 }, { /* sentinel */ } }; static const struct serdev_device_ops rave_sp_serdev_device_ops = { .receive_buf = rave_sp_receive_buf, .write_wakeup = serdev_device_write_wakeup, }; static int rave_sp_probe(struct serdev_device *serdev) { struct device *dev = &serdev->dev; const char *unknown = "unknown\n"; struct rave_sp *sp; u32 baud; int ret; if (of_property_read_u32(dev->of_node, "current-speed", &baud)) { dev_err(dev, "'current-speed' is not specified in device node\n"); return -EINVAL; } sp = devm_kzalloc(dev, sizeof(*sp), GFP_KERNEL); if (!sp) return -ENOMEM; sp->serdev = serdev; dev_set_drvdata(dev, sp); sp->variant = of_device_get_match_data(dev); if (!sp->variant) return -ENODEV; mutex_init(&sp->bus_lock); mutex_init(&sp->reply_lock); BLOCKING_INIT_NOTIFIER_HEAD(&sp->event_notifier_list); serdev_device_set_client_ops(serdev, &rave_sp_serdev_device_ops); ret = devm_serdev_device_open(dev, serdev); if (ret) return ret; serdev_device_set_baudrate(serdev, baud); serdev_device_set_flow_control(serdev, false); ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE); if (ret) { dev_err(dev, "Failed to set parity\n"); return ret; } ret = rave_sp_get_status(sp); if (ret) { dev_warn(dev, "Failed to get firmware status: %d\n", ret); sp->part_number_firmware = unknown; sp->part_number_bootloader = unknown; } /* * Those strings already have a \n embedded, so there's no * need to have one in format string. */ dev_info(dev, "Firmware version: %s", sp->part_number_firmware); dev_info(dev, "Bootloader version: %s", sp->part_number_bootloader); return devm_of_platform_populate(dev); } MODULE_DEVICE_TABLE(of, rave_sp_dt_ids); static struct serdev_device_driver rave_sp_drv = { .probe = rave_sp_probe, .driver = { .name = "rave-sp", .of_match_table = rave_sp_dt_ids, }, }; module_serdev_device_driver(rave_sp_drv); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>"); MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>"); MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>"); MODULE_DESCRIPTION("RAVE SP core driver");